Seoul: Seoul stocks ended higher for the second consecutive session Wednesday on an extended chip rally ahead of upcoming earnings releases from U.S. big tech companies. The Korean won fell against the U.S. dollar.

According to Yonhap News Agency, the benchmark Korea Composite Stock Price Index (KOSPI) closed up 49.75 points, or 0.74 percent, to 6,797.7 after rising as high as 7,166.00. After opening sharply higher, the index shed some of the early gains as retail and institutional investors sold off tech heavyweights to lock in profits. The two entities sold off a combined net 2.61 trillion won (US$1.8 billion), while foreigners snatched up a net 2.62 trillion won.

Trade volume was moderate at 368.7 million shares worth 28.1 trillion won, with winners outnumbering losers 467 to 398. "The KOSPI returned some of its earlier advance in the face of rising global oil prices, and as investors took a cautious stance ahead of the earnings release from Alphabet," said Lee Kyoung-min, an analyst from Daishin Securities. Alphabet, the parent company of Google, is expected to release its second-quarter earnings results Wednesday (U.S. time).

Along with persisting tensions in the Middle East, investors were cautious over uncertainties related to Washington's global tariffs of 10 percent, scheduled to expire later this week. In Seoul, market heavyweights ended mixed. Top-cap Samsung Electronics inched up 0.58 percent to 260,500 won, while industry rival SK hynix dipped 0.33 percent to 1,830,000 won.

Companies in the robotics sector gained ground following an announcement from Samsung Electronics about plans to strengthen its robotics business. Hyundai Motor, which owns the robotics company Boston Dynamics, advanced 4.76 percent to 418,000 won and LG Electronics climbed 5.48 percent to 182,700 won. Among the decliners were Samsung Biologics, which fell 1.65 percent to 1,372,000 won, and defense giant Hanwha Aerospace, which declined 0.89 percent to 891,000 won.

The Korean won was quoted at 1,480.1 won against the U.S. dollar, down 6.7 won from the previous session.